Vanguard Formation

From Wikipedia, the free encyclopedia
  (Redirected from Masefield Shale)
Jump to: navigation, search
Vanguard Formation
Stratigraphic range: Callovian to Oxfordian
Type Geological formation
Sub-units Masefield Shale
Roseray Formation
Rush Lake Shale
Underlies Mannville Group
Overlies Shaunavon Formation
Thickness up to 180 metres (590 ft)[1]
Lithology
Primary Shale, sandstone
Location
Coordinates 49°22′N 107°47′W / 49.36°N 107.79°W / 49.36; -107.79 (Vanguard Formation)Coordinates: 49°22′N 107°47′W / 49.36°N 107.79°W / 49.36; -107.79 (Vanguard Formation)
Region WCSB, Williston Basin
Country  Canada
 United States
Type section
Named for Vanguard, Saskatchewan
Named by R.L. Milner and G.E. Thomas, 1954

The Vanguard Formation is a stratigraphical unit of Callovian to Oxfordian age in the Western Canadian Sedimentary Basin.

It takes the name from Vanguard, and was first defined by R.L. Milner and G.E. Thomas in 1954.[2]

Lithology[edit]

The Vanguard Formation is composed of calcareous shale with a median quartzose sandstone. [1]

Distribution[edit]

The Vanguard Formation Lateral reaches a maximum thickness of 180 metres (590 ft) in the Williston Basin along the Saskatchewan/Montana border.[1]

Relationship to other units[edit]

The Vanguard Formation is unconformably overlain by the Mannville Group and disconformably overlays the Shaunavon Formation.[1]

It is equivalent to the Ellis Group in Montana and North Dakota.

Subdivisions[edit]

in south-western Saskatchewan, Vanguard has group status, and includes the following subdivisions (of formation rank):

References[edit]

  1. ^ a b c d Lexicon of Canadian Geologic Units. "Vanguard Formation". Retrieved 2010-01-01. 
  2. ^ Milner, R.L. and Thomas, G E., 1954. Jurassic System in Saskatchewan. In: Western Canada Sedimentary Basin. American Association of Petroleum Geologists, p. 250-267